ABSTRACT
Experimental designs are school psychologists’ best methods for detecting and measuring any causal relationships between independent variables (IVs) and dependent variables (DVs). To verify the emphasis on experimental design within education in the United States, one need look no further than the Every Student Succeeds Act of 2015, which repeatedly and interchangeably refers to high-quality research, scientifically based research, and evidence-based research. Random assignment can be difficult to accomplish in school-based research, although Shadish et al. identified several situations conducive to randomized experiments, including those in which demand outstrips supply, units are isolated, or change is mandated and solutions are acknowledged to be unknown. Randomized control trials and quasi-experimental research designs are often depicted using a common set of symbols to indicate assignment to groups, time points for measurement, and types of treatment. Within each depiction, each row represents a specific group.
